There are hundreds of websites for kids... almost too many to wade through to find the good ones.
Here are a few of my favorites for the classroom:
I LOVE LOVE LOVE this site! So much to explore and learn!
Great for math and reading! I
use this every year.
This math game is my students' all time favorite. They BEG to play and will even skip recess for it!
I use this one during reading centers and sometimes for homework. You can assign articles or kids can choose their own based on interest.
Newsela is similar to Tween Tribune with interested articles for kids to read.
For more ideas, visit my Pinterest board: Classroom Technology